The invention relates generally to power-driven conveyors and, more particularly, to modular conveyor belts constructed of a series of rows of belt modules split into multiple pieces and connected together by hinge pins.
Conventional modular conveyor belts and chains are constructed of modular links, or belt modules, arranged end to end and often side by side in belt rows. The modules typically extend from a top article-engaging surface to a bottom drive surface through their thickness. Spaced-apart hinge eyes extending from each end of the modules include aligned openings. The hinge eyes along one end of a row of modules are interleaved with the hinge eyes along one end of an adjacent row. Pivot rods, or hinge pins, journalled in the aligned openings of interleaved hinge eyes, connect adjacent rows together end to end to form a conveyor belt capable of articulating about a drive sprocket or drum at the hinge formed by the interleaved hinge eyes between adjacent belt rows.
Although each belt row may include a single module defining the width of the belt, often each row includes a number of modules arranged side by side with a seam between them. Usually these belt modules composing the belt are arranged in a bricklay pattern to avoid a continuous longitudinal seam running the length of the belt. Such continuous seams would significantly decrease the beam strength of the belt. But, even in bricklayed modular belts, the seams in each row decrease the beam strength of the row. Furthermore, as the connecting hinge pins grow, the belt width can change because the modules have freedom to slide laterally and separate from each other at the seams. Besides varying the width of the belt, this separation can cause trip edges for products, pinch points for fingers, or gaps into which small conveyed products can fall or get caught.
Although most belt modules are made out of a homogenous material, such as metal or plastic, other belt modules are made of more than one material. For example, some belt modules include a resilient high-friction material molded, bonded, or otherwise attached to a slick low-friction plastic base. Belts made of these modules are useful, for example, in conveying articles up inclines and down declines. But complex molding techniques or messy secondary manufacturing steps are required to make the attachment.
To satisfy other applications, belt modules are often designed with moving parts that interact with conveyed products. Examples include belts with rollers for low backline pressure or for product indexing or offloading. Once again, special manufacturing or molding steps are necessary to install these moving parts. In the case of some modular plastic roller-top belts, rollers are mounted on a metal axle that extends through support stanchions spaced apart across the module. The module is manufactured by carefully molding the module and its stanchions around the axle and rollers. When the molding is complete, the axle is held permanently in the stanchions. If a roller or stanchion is damaged, the module has to be removed from the belt and replaced. Repair is not possible.
Thus, in view of these shortcomings, there is a need for a conveyor belt that may include a variety of accessories, even movable parts, and that is easy to manufacture and to repair in the field. There is also a need for a modular conveyor belt that exhibits even greater beam strength than a conventional bricklaid belt.